Quote Originally Posted by mrs767er View Post
That is why it's not zone to zone--the taxes change--maybe ZRH and MXP are close in a zone but the taxes are different
I'm not sure I follow you. DL collects the airport fees/taxes after you travel, so it wouldn't matter where you wanted to go, only where you went.

As I read DL's ZED agreement as long as you stay in a zone the price is the same. The only thing that would change it is if one were travel through a connecting city that moved the mileage into the next zone. (Disclosure- I've only used a ZED ticket once CDG-MUC, so maybe I'm missing something)